Mass-analyzed ion kinetic energy spectra of alkoxide and carboxylate ions were obtained after collisional excitation. The positive ions detected implied the formation of unusual oxenium and acyloxy ions, respectively. The collision-induced dissociations of the M plus 1 ions resulting from chemical ionization of aliphatic esters were studied to gain knowledge concerning the fragmentation of even-electron ions. Computer programs have been developed in cooperation with Finnigan Corporation which permit data system acquisition and processing of ion kinetic energy spectra.